redline

[eq]

Anyone want to comment on how the redline is implemented on our scoots? I've noticed that I 'redline' on my 2006 Metro at about 9140 rpms - that's the highest engine speed I've seen logged on my digital tach, before something happens. It seems like, under conditions where I'd actually be able to go beyond the 9140, such as, certainly, going down a steep hill, the ECM sends fewer sparks to the engine - or something like that. The tach reading drops real low, such as if there isn't a spark on every revolution any longer... The main thing I'm curious about is just that I always read that the 06+ Mets and Ruckii redline at 8850. I can consistently go beyond that, and I seem to be able to hold beyond that as well (i.e. I could hold it at say 9100, rather than just blipping up to 9100 for a second or two)...

[Dandy Dan]

My 06 always cut out right at 8850rpm....I'm not sure why your Met goes higher. I according to the Ruckus Guru, Chanito, the ECM inforces the redline by cutting every 3rd spark so you lose a lot of your power.

[eq]

Thanks. Anyone else have insights?

[timberwolfmadcat]

I haven't installed my Veypor yet so i dont have a tach... my redline speed seems to be consistently higher than most rucks as well... i was able to do about 45-46 MPH once she was warmed up stock... now im thinking i mighta got a MET ECU Interesting nonetheless

[chanito]

This is what is called soft redlining, or power limiting, as the engine reaches the engine speed that is set as the limit, the ECM stop sending the signal coil once every 3 sparks, it work different sometimes because the ruckus/metropolitan engine have what is called a waste spark ignition, which means that the coil fires every revolution but since we have a 4 cycle engine in one revolution the spark is WASTED on the exhaust cycle, and that is the reason why it have to skip on an uneven number, because if it was an even number the engine might get lucky and it will use all of the non firing strokes to happen in the exhaust cycle and your engine will keep revving along happily, since the engines have momentum, sometimes this momentum will allow under the right condition for the engine to keep revving higher and them cut back to the rev limit, some tachs might make the ignition pulse signal weaker fooling the ECM into allowing more rpms before implementing the rev limiter policy, just be careful and you should be OK

[eq]

Thanks all... Today (yesterday) I hit the redline earlier. Go figure. It felt like it was 'missing'/misfiring, I think it was at 8900 or 9000, definitely not 9140... Is the redline a cut and dried value, the ECM programmed to cut the spark at 8850, or might it be related to other things, like the throttle position, maybe engine temp?

[chanito]

eq said:

Thanks all... Today (yesterday) I hit the redline earlier. Go figure. It felt like it was 'missing'/misfiring, I think it was at 8900 or 9000, definitely not 9140... Is the redline a cut and dried value, the ECM programmed to cut the spark at 8850, or might it be related to other things, like the throttle position, maybe engine temp?

For that specific info, you will have to get in touch with the Honda tech department and ask for the ECM protocol on rev control, i doubt they will give the info, but you might be lucky

[eq]

More thoughts on this subject... After cruising on the highway for a long ride, I really get the impression that the redline isn't a cut and dried threshold. During this ride I got a chance to experience top speed under varying circumstances, such as into headwinds, on flats, up and down slopes. It seems as though, if the engine isn't stressed I can hold a higher rpm consistently, but if the engine is stressed, I get the spark-cut effect. Along most of this trip I was able to hold 9100 rpms. At one time I hit 9200. At other times, at WOT, I'd get the spark cut at 8850. It seemed like I could usually get the highest consistent top speeds when I rolled slightly back on the throttle and didn't push it... MY sense is that the redline is partly governed by throttle position - at least, knowing that that's one of 2 sensors we have. Maybe engine temp is used as well. In any event, there's just no way it's a cut and dried value - hit 8850 and the spark cuts. That doesn't happen to me, ever...

[Dandy Dan]

Hmm....mine's always felt cut and dried at 8850rpm but then again, I'm always at WOT too so perhaps the throttle position does have something to do with it. You must be cruising pretty good if you were holding 9100 RPM for most of the trip.

[eq]

It seems clear on my scoot, with my tach, when the redline kicks in. The tach reading will drop way down because all of a sudden 1 out of 3 sparks in the numerator for the calculation of average engine speed, over the half second or so sample period, is gone... There's no way for the tach to keep a steady, say, 9100 if the redline were kicking in. So I'd be doing 9100 rpms and all of a sudden RPM reading will drop to like 8200, 7500, etc; if I roll off the throttle it will jump back to normal rpms in a second or 2...

[Dandy Dan]

Yeah my RPMs rise up to 8850 and then when they hit 8850 the tach reading (Digital tach) becomes very jumbled.